A Case-control Study On The Relationship Between MDR1 Gene Polymorphism And Risk Of Bladder And Kidney Cancer

Objective To investigate the relationship between multidrug resistance(MDR1)gene polymorphism and susceptibility of bladder and kidney cancer.Methods 1.A hospital-based matched case-control study was carried out.135 hospitalized patients with bladder cancer and 69 hospitalized patients with kidney cancer were enrolled in Inner Mongolia Medical University affiliated Hospital and People’s Hospital of Inner Mongolia between January 2018 and October 2018.135 healthy subjects underwent medical examination in above hospitals were collected as control.The cases and controls had been matched on sex and age.All the subjects signed the informed consent.2.Data were collected through questionnaire,which including name,gender,nationality,age,height,weight,cultural level,occupational history,previous medical history,smoking,drinking,diet condition and family heredity history.3.The polymorphism of MDR1 loci were detection as follows:(1)Extraction of genomic DNA: 2ml peripheral blood was extracted in EDTA anticoagulant tube on empty stomach at early morning.The whole blood genomic DNA were extracted with Bioteke whole blood DNA rapid extraction kit(200 times).Genomic DNA purity were identified by electrophoresis,and DNA concentration was detected by nucleic acid quantitative instrument.(2)The imLDR method was used to detect the polymorphisms of four MDR1 genes,including rs1045642,rs1128503,rs2032582 and rs3842.4.Determination of P-glycoprotein(P-gp)expression: 5ml peripheral blood was extracted in the sodium citrate coagulation test tube on empty stomach at early morning.And P-gp expression was detected by human P-glycoprotein/permeable glycoprotein(P-gp)ELISA kit.5.Determination of mRNA expression level of MDR1 gene in case tissues:(1)The total RNA extraction kit was used to extract RNA from the cancerous and paracarcinomatous tissues of renal cancer patients.RNA concentration were detected by nucleic acid quantitative instrument.(2)RNA were reversely transcribed intocDNA using the tiangen reverse transcription kit.The relative expression of mRNA in MDR1 gene was determined by RT-PCR.6.Statistical treatment: SPSS25.0 statistical software package was used for statistical analysis,measurement data were expressed by "mean value and standard deviation",and count data were expressed by the number of cases(percentage).The differences in age and BMI between the case and control group were analyzed.When comparing measurement data between the two groups,paired t test was used for normal distribution,while rank sum test was used for non-normal distribution.Qualitative data between the two groups were compared by chi-square test,the distribution of allele and genotype frequency for loci of MDR1 in two groups,including rs1045642,rs1128503,rs2032582 and rs3842,were analyzed by chi-square test.Multivariate Logistic regression was used to calculate Odds Ratio(OR)and 95%Confidence Interval(CI)to evaluate the relationship among previous medical history,smoking,drinking,diet condition and family heredity history and the risk of bladder and kidney cancer.Results1.In bladder cancer cases and corresponding controls,there were no statistical significance among sex,age,nationality,drinking,consumption of dairy products,daily water consumption,hair dye,use air fresheners without statistical significance(P > 0.05).However,there were statistical difference among cultural level,BMI,smoking,food flavor,edible fruit,vegetable collocation,edible oil,drinking water source,a full bladder,cooking heating fuel(P < 0.05).In kidney cancer cases and corresponding controls,there were no statistical significance among sex,age,BMI,smoking,drinking alcohol,food taste,consumption of dairy products,water quantity,hair color,a full bladder,use air fresheners,cooking heating fuel no statistical significance(P > 0.05),However,there were statistical difference among cultural level,ethnic,edible fruit,vegetable collocation,edible oil,drinking water source(P <0.05).2.The distribution of allele and genotype frequency of MDR1 gene at four loci,rs1045642,rs1128503,rs2032582 and rs3842 were not statistically significant(P >0.05)in the bladder cancer and the control group.MDR1 gene rs1045642,rs2032582 and rs3842 loci showed no significant difference in the case and the control group in genotype frequency and allele frequency in kidney cancer groups(P > 0.05).For rs1128503 locus,the genotype frequency(χ2=6.563,P=0.038)was statistically significant between the two groups(P < 0.05),while the allele frequency was notstatistically significant in kidney cancer groups(P > 0.05).3.Conditional logistic regression showed that BMI(≥24),salty diet,cooking with animal oil and holding back urine were risk factors for bladder cancer(OR=1.138,2.474,1.576,1.820).Excessive meat consumption and the using of animal oils were risk factors for kidney cancer(OR=5.475,3.158).4.Serum P-gp concentration was detected by ELISA.The serum P-gp expression in bladder cancer patients were significantly higher than that in the control group,(P< 0.05).The serum P-gp protein expression in patients with kidney cancer patients were also higher than that in the control group,the difference was statistically significant(P < 0.05).5.There was no statistically significant difference in mRNA relative content in cancerous and paracarcinomatous tissues of kidney cancer patients(P > 0.05).Conclusion1.BMI,salty diet,cooking with animal oil and holding back urine are risk factors for bladder cancer;Excessive meat consumption and using of animal oils are risk factors for kidney cancer.2.The case control study shows that polymorphisms of four sites of MDR1 gene,rs1045642,rs1128503,rs2032582 and rs3842,were not related to the incidence of bladder and kidney cancer.3.The expression of P-gp protein in MDR1 gene were significantly higher in bladder and kidney cancer group than that in the control group.4.There was no difference in mRNA expression between cancerous and paracarcinomatous tissues in kidney cancer patients.